1. Technical Field
The disclosure generally relates to membrane electrode assemblies and biofuel cell using the same, and particularly, to a membrane electrode assembly based on carbon nanotubes and a biofuel cell using the same.
2. Description of Related Art
Fuel cells can generally be classified into alkaline, solid oxide, and proton exchange membrane fuel cells. The proton exchange membrane fuel cell has received increasingly more attention and has developed rapidly in recent years. Typically, the proton exchange membrane fuel cell includes a number of separated fuel cell work units. Each work unit includes a fuel cell membrane electrode assembly (MEA), flow field plates (FFP), current collector plates (CCP), as well as related support equipment, such as blowers, valves, and pipelines.
Referring to FIG. 12, a biofuel cell, which is a specific type of proton exchange membrane fuel cell, is disclosed by the prior art. The biofuel cell includes a fuel electrode 1, electroanalysis layer 3 and a gas electrode 5. The electroanalysis layer 3 has two opposite surfaces. The fuel electrode 1 is located adjacent to one surface of the electroanalysis layer 3. The gas electrode 5 is located adjacent to the opposite surface of the electroanalysis layer 3. The fuel electrode 1 includes a diffusion layer 11 and a container (not marked) filled with enzymatic catalyst (not show) and biofuel (not show). The electroanalysis layer 3 is made of proton exchange membrane. The gas electrode 5 includes a diffusion layer (not show) and a catalyst layer (not show) located adjacent to the diffusion layer. The diffusion layer 11 of the fuel electrode 1 is typically made of glass like carbon having a plurality of micropores.
In working process of the biofuel cell, the enzymatic catalyst decomposes a biofuel to form electrons and protons (H+). The protons are transferred by the electroanalysis layer 3 from fuel electrode 1 to gas electrode 5. At the same time, the electrons arrive at the gas electrode 5 by an external electrical circuit. In the gas electrode 5, oxygen is applied. Thus, the oxygen reacts with the protons and electrons as shown in the following equation: ½O2+2H++2e→H2O.
However, the glass like carbon has the following disadvantages. Firstly, the micropores in the glass like carbon are not uniform. Thus, the structure prevents the diffusion layer from uniformly diffusing the biofuel and/or gases that are needed for the MEA to function efficiently. Secondly, the glass like carbon has high electrical resistance, thereby the travel of electrons between the diffusion layer and the external electrical circuit is restricted. As a result, the reaction activity of the MEA is reduced.
What is needed, therefore, are a membrane electrode assembly and a biofuel cell using the same having improved reaction activity.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one present embodiment of the membrane electrode assembly and biofuel cell using the same, in at least one form, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner.